Currently the forum gets more spam than "real" posts every day. Many forums provide a plugin or setting allowing new users to post links only after a number of legitimate posts, maybe that would be a good idea for this one, too?

I would like to agree with you. I would really like to. However as long programs you need sometimes hide their only windows in the systray after launching leaving you no other option to make them visible (thinking of Pidgin and, if you're unlucky enough to have pressed Ctrl-w, also clementine) you need this thing - whether you like it or not.
Problem is that nowadays a lot of software we use is designed for use with Gnome in which the systray is central and mandatory. Hence e better make it work

That would be great. There's also a second theme, VulcanRetro E20, that is based largely on identical code (what I did with blingbling-e20 I did with VulcanRetro E20, too). I guess that after analyzing your changes, filling the gaps in that one will be rather easy.

Yep, you're absolutely right. I found it "good enough" for my daily work and worthwhile publishing since there's hardly anything for 20 out there.
Excellent work, thank you for having made this much more complete now!

In many cases it is indeed images, and I might try this. Actually I rather like this color in many places, e.g. in the pager this looks pretty charming.
However I will probably still work on another update where the tasks applet is styled. I played around with it a little bit (used the code from the 'default' theme replacing some images), but the result is not good yet. If I use the 'blingblng' button image for unselected tasks, I still get this strange black frame around it which looks rather bad. Also I have not found out how to style the currently selected task, there does not seem to be an image used, but I haven't really had enough time to dig deeper into this.

Thank you very much again!
There are a couple of "classic" themes that I would really like to see on e20 (SpiffE and ShinyMetal are on top of my list). However it seems like a "from the scratch" approach of deriving from the standard theme will probably be a better idea.
I must say that from what I have seen I am not terribly happy with the way it is in e20. It seems like they're in middle of moving more and more into ELEMENTARY. Right now it looks like one has to repeat oneself far too often.
Anyway for now I'm happy with those two I have. Usually I do stuff like this during the christmas break

Hey, thank you very much! I have actually found pretty much the same solution to this and was just about to share this here
I ported some of rpil's code (from his derivation of the Vulcan theme) which essentially contains the same stuff.
I am going to release prerelease 0.8 of the Vulcan Retro and blingbling themes on my github account and e17-stuff.org. There are of course still some open issues, but I've been using those both (in particular blingbling) for some weeks now and I really enjoy them.
From the e-dev mailing list I have learned that there have been quite a few changes to the way colors are dealt with (they propose to introduce color schemes the same way as in the default theme which does make sense will involve quite a bit of work). Hence there are still quite a few colors set from the default theme that have not been overridden in the themes (basically because for each of them I spend a LOT of time searching and I simply don't have the time to do this, also in some cases this actually looks pretty good). I'll publish more verbose lists of known issues on github when I release them.
I could do with some contributions. For instance I am not very good at image editing, and the background image for selected menu entries does not look very good. In many places the blue glow effect from the default theme shows (e.g. in the pager, task list, also font colors, as mentioned above). Also there are widgets not yet styled, e.g. the system dialog, the digital clock.
I will now slow down a little bit. As said, the themes look good (enough) for me, and due to the 80–20 rule future enhancements will come at a much higher price which I will probably not be able to invest (need to make a living).
Here's two more screenshots of the two themes:
Vulcan Retro with file manager (note the blue-glow digital clock and highlight of the active element in the shelf):
Blingbling with big analog clock and taskbar/pager on desktop (note the sub-optimal background graphic for the active menu element and the glow-blue highlight of active desktop and window)::

I found one issue in the two themes I am working on. In both, the file manager appears as an empty white window. I did not notice that earlier because I practically never use file managers
This seems strange, because in most cases I've seen so far things would display with the default theme. Here I see nothing.
Again - anyone knows what the reason for this could be? The Theme migration checklist only mentions a signal change for the fileman, that does not look like the reason...